emissions of air pollutants, annual growth rate in Iran
Iran: emissions of air pollutants, annual growth rate was 3.51 % change on previous year in 2022. ◆ Volatile
emissions of air pollutants, annual growth rate in Iran, 1751–2022
Source: Statizoid (derived). Measured in % change on previous year.
Analysis
The most recent figure for emissions of air pollutants, annual growth rate in Iran is 3.51 % change on previous year, measured in 2022.
The figure is up 41.1% on the previous year and up 10.2% over ten years.
Over the whole period, emissions of air pollutants, annual growth rate in Iran peaked at 67.64 % change on previous year in 1956 and was at its lowest, -14.68 % change on previous year, in 1980.
Iran ranks 22nd of 219 countries on this measure, in the top 10%.
The series is highly variable year to year, so single readings are best treated with caution.
emissions of air pollutants, annual growth rate in Iran, year by year
| Year | % change on previous year | Change |
|---|---|---|
| 1751 | 0.1761 % change on previous year | — |
| 1752 | 0.1758 % change on previous year | -0.2% |
| 1753 | 0.1755 % change on previous year | -0.2% |
| 1754 | 0.1746 % change on previous year | -0.5% |
| 1755 | 0.1743 % change on previous year | -0.2% |
| 1756 | 0.174 % change on previous year | -0.2% |
| 1757 | 0.1737 % change on previous year | -0.2% |
| 1758 | 0.1729 % change on previous year | -0.5% |
| 1759 | 0.1726 % change on previous year | -0.2% |
| 1760 | 0.1723 % change on previous year | -0.2% |
| 1761 | 0.1725 % change on previous year | +0.1% |
| 1762 | 0.1722 % change on previous year | -0.2% |
| 1763 | 0.1719 % change on previous year | -0.2% |
| 1764 | 0.1711 % change on previous year | -0.5% |
| 1765 | 0.1708 % change on previous year | -0.2% |
| 1766 | 0.1706 % change on previous year | -0.2% |
| 1767 | 0.1698 % change on previous year | -0.5% |
| 1768 | 0.17 % change on previous year | +0.1% |
| 1769 | 0.1687 % change on previous year | -0.8% |
| 1770 | 0.1689 % change on previous year | +0.1% |
| 1771 | 0.1686 % change on previous year | -0.2% |
| 1772 | 0.1683 % change on previous year | -0.2% |
| 1773 | 0.168 % change on previous year | -0.2% |
| 1774 | 0.1678 % change on previous year | -0.2% |
| 1775 | 0.167 % change on previous year | -0.5% |
| 1776 | 0.1662 % change on previous year | -0.5% |
| 1777 | 0.1664 % change on previous year | +0.1% |
| 1778 | 0.1657 % change on previous year | -0.5% |
| 1779 | 0.1649 % change on previous year | -0.5% |
| 1780 | 0.1646 % change on previous year | -0.2% |
| 1781 | 0.1648 % change on previous year | +0.1% |
| 1782 | 0.1641 % change on previous year | -0.5% |
| 1783 | 0.1638 % change on previous year | -0.2% |
| 1784 | 0.1631 % change on previous year | -0.5% |
| 1785 | 0.1628 % change on previous year | -0.2% |
| 1786 | 0.1625 % change on previous year | -0.2% |
| 1787 | 0.1618 % change on previous year | -0.5% |
| 1788 | 0.161 % change on previous year | -0.5% |
| 1789 | 0.1613 % change on previous year | +0.1% |
| 1790 | 0.1605 % change on previous year | -0.5% |
| 1791 | 0.1598 % change on previous year | -0.5% |
| 1792 | 0.1595 % change on previous year | -0.2% |
| 1793 | 0.1588 % change on previous year | -0.5% |
| 1794 | 0.1585 % change on previous year | -0.2% |
| 1795 | 0.1578 % change on previous year | -0.5% |
| 1796 | 0.1576 % change on previous year | -0.2% |
| 1797 | 0.1573 % change on previous year | -0.2% |
| 1798 | 0.1566 % change on previous year | -0.5% |
| 1799 | 0.1563 % change on previous year | -0.2% |
| 1800 | 0.1556 % change on previous year | -0.5% |
| 1801 | 0.1549 % change on previous year | -0.5% |
| 1802 | 0.1542 % change on previous year | -0.5% |
| 1803 | 0.1535 % change on previous year | -0.5% |
| 1804 | 0.1532 % change on previous year | -0.2% |
| 1805 | 0.153 % change on previous year | -0.2% |
| 1806 | 0.1523 % change on previous year | -0.5% |
| 1807 | 0.1521 % change on previous year | -0.2% |
| 1808 | 0.1514 % change on previous year | -0.5% |
| 1809 | 0.1507 % change on previous year | -0.5% |
| 1810 | 0.1504 % change on previous year | -0.2% |
| 1811 | 0.1493 % change on previous year | -0.8% |
| 1812 | 0.1481 % change on previous year | -0.8% |
| 1813 | 0.1484 % change on previous year | +0.2% |
| 1814 | 0.1472 % change on previous year | -0.8% |
| 1815 | 0.147 % change on previous year | -0.1% |
| 1816 | 0.1468 % change on previous year | -0.1% |
| 1817 | 0.1461 % change on previous year | -0.5% |
| 1818 | 0.1454 % change on previous year | -0.5% |
| 1819 | 0.1452 % change on previous year | -0.1% |
| 1820 | 0.1446 % change on previous year | -0.5% |
| 1821 | 0.4967 % change on previous year | +243.6% |
| 1822 | 0.4933 % change on previous year | -0.7% |
| 1823 | 0.49 % change on previous year | -0.7% |
| 1824 | 0.4867 % change on previous year | -0.7% |
| 1825 | 0.4839 % change on previous year | -0.6% |
| 1826 | 0.4806 % change on previous year | -0.7% |
| 1827 | 0.4779 % change on previous year | -0.6% |
| 1828 | 0.4747 % change on previous year | -0.7% |
| 1829 | 0.4716 % change on previous year | -0.7% |
| 1830 | 0.4685 % change on previous year | -0.7% |
| 1831 | 0.4593 % change on previous year | -2.0% |
| 1832 | 0.4563 % change on previous year | -0.6% |
| 1833 | 0.4533 % change on previous year | -0.6% |
| 1834 | 0.4504 % change on previous year | -0.6% |
| 1835 | 0.4476 % change on previous year | -0.6% |
| 1836 | 0.4447 % change on previous year | -0.6% |
| 1837 | 0.4423 % change on previous year | -0.5% |
| 1838 | 0.4395 % change on previous year | -0.6% |
| 1839 | 0.4367 % change on previous year | -0.6% |
| 1840 | 0.434 % change on previous year | -0.6% |
| 1841 | 0.4241 % change on previous year | -2.3% |
| 1842 | 0.4211 % change on previous year | -0.7% |
| 1843 | 0.4189 % change on previous year | -0.5% |
| 1844 | 0.4163 % change on previous year | -0.6% |
| 1845 | 0.4138 % change on previous year | -0.6% |
| 1846 | 0.4108 % change on previous year | -0.7% |
| 1847 | 0.4087 % change on previous year | -0.5% |
| 1848 | 0.4063 % change on previous year | -0.6% |
| 1849 | 0.4034 % change on previous year | -0.7% |
| 1850 | 0.5694 % change on previous year | +41.2% |
| 1851 | 0.3093 % change on previous year | -45.7% |
| 1852 | 0.3043 % change on previous year | -1.6% |
| 1853 | 0.2994 % change on previous year | -1.6% |
| 1854 | 0.2945 % change on previous year | -1.6% |
| 1855 | 0.2901 % change on previous year | -1.5% |
| 1856 | 0.2932 % change on previous year | +1.1% |
| 1857 | 0.288 % change on previous year | -1.8% |
| 1858 | 0.2836 % change on previous year | -1.5% |
| 1859 | 0.2785 % change on previous year | -1.8% |
| 1860 | 0.2734 % change on previous year | -1.8% |
| 1861 | 0.2683 % change on previous year | -1.8% |
| 1862 | 0.2629 % change on previous year | -2.0% |
| 1863 | 0.2584 % change on previous year | -1.7% |
| 1864 | 0.2534 % change on previous year | -1.9% |
| 1865 | 0.2485 % change on previous year | -1.9% |
| 1866 | 0.2514 % change on previous year | +1.2% |
| 1867 | 0.2465 % change on previous year | -1.9% |
| 1868 | 0.2413 % change on previous year | -2.1% |
| 1869 | 0.2365 % change on previous year | -2.0% |
| 1870 | 0.2317 % change on previous year | -2.0% |
| 1871 | 1.2 % change on previous year | +418.8% |
| 1872 | 1.18 % change on previous year | -1.9% |
| 1873 | 1.16 % change on previous year | -1.9% |
| 1874 | 1.13 % change on previous year | -1.9% |
| 1875 | 1.11 % change on previous year | -1.9% |
| 1876 | 1.11 % change on previous year | -0.3% |
| 1877 | 1.09 % change on previous year | -1.9% |
| 1878 | 1.07 % change on previous year | -1.9% |
| 1879 | 1.05 % change on previous year | -1.9% |
| 1880 | 1.03 % change on previous year | -1.9% |
| 1881 | 1.02 % change on previous year | -1.3% |
| 1882 | 0.9971 % change on previous year | -1.9% |
| 1883 | 0.9782 % change on previous year | -1.9% |
| 1884 | 0.9598 % change on previous year | -1.9% |
| 1885 | 0.9421 % change on previous year | -1.8% |
| 1886 | 0.9405 % change on previous year | -0.2% |
| 1887 | 0.923 % change on previous year | -1.9% |
| 1888 | 0.9053 % change on previous year | -1.9% |
| 1889 | 0.8887 % change on previous year | -1.8% |
| 1890 | 0.872 % change on previous year | -1.9% |
| 1891 | 0.6297 % change on previous year | -27.8% |
| 1892 | 0.6174 % change on previous year | -2.0% |
| 1893 | 0.6054 % change on previous year | -2.0% |
| 1894 | 0.5932 % change on previous year | -2.0% |
| 1895 | 0.5812 % change on previous year | -2.0% |
| 1896 | 0.5854 % change on previous year | +0.7% |
| 1897 | 0.5732 % change on previous year | -2.1% |
| 1898 | 0.561 % change on previous year | -2.1% |
| 1899 | 0.5496 % change on previous year | -2.0% |
| 1900 | 0.538 % change on previous year | -2.1% |
| 1901 | -1.8 % change on previous year | -433.8% |
| 1902 | -1.87 % change on previous year | +3.9% |
| 1903 | -1.94 % change on previous year | +3.9% |
| 1904 | -2.01 % change on previous year | +3.9% |
| 1905 | -2.09 % change on previous year | +3.9% |
| 1906 | -2.16 % change on previous year | +3.2% |
| 1907 | -2.25 % change on previous year | +4.0% |
| 1908 | -2.34 % change on previous year | +4.0% |
| 1909 | -2.43 % change on previous year | +4.1% |
| 1910 | -2.53 % change on previous year | +4.1% |
| 1911 | -1.41 % change on previous year | -44.4% |
| 1912 | -1.5 % change on previous year | +6.4% |
| 1913 | -1.55 % change on previous year | +3.7% |
| 1914 | -1.67 % change on previous year | +7.3% |
| 1915 | -1.77 % change on previous year | +6.3% |
| 1916 | -1.69 % change on previous year | -4.5% |
| 1917 | -1.79 % change on previous year | +5.7% |
| 1918 | -1.92 % change on previous year | +7.1% |
| 1919 | -2.02 % change on previous year | +5.3% |
| 1920 | -2.12 % change on previous year | +5.2% |
| 1921 | -2.19 % change on previous year | +3.0% |
| 1922 | -2.31 % change on previous year | +5.5% |
| 1923 | -2.41 % change on previous year | +4.6% |
| 1924 | -2.6 % change on previous year | +7.7% |
| 1925 | -3.04 % change on previous year | +17.1% |
| 1926 | -3.25 % change on previous year | +6.8% |
| 1927 | -3.39 % change on previous year | +4.4% |
| 1928 | -3.7 % change on previous year | +9.0% |
| 1929 | -4.14 % change on previous year | +11.8% |
| 1930 | -4.2 % change on previous year | +1.4% |
| 1931 | -4.78 % change on previous year | +13.8% |
| 1932 | -4.8 % change on previous year | +0.5% |
| 1933 | -5.2 % change on previous year | +8.2% |
| 1934 | -5.69 % change on previous year | +9.6% |
| 1935 | -6.4 % change on previous year | +12.5% |
| 1936 | -6.63 % change on previous year | +3.4% |
| 1937 | -7.12 % change on previous year | +7.5% |
| 1938 | -8.86 % change on previous year | +24.4% |
| 1939 | 0.9137 % change on previous year | -110.3% |
| 1940 | 1.04 % change on previous year | +13.3% |
| 1941 | -2.7 % change on previous year | -360.3% |
| 1942 | -0.7497 % change on previous year | -72.2% |
| 1943 | -3.07 % change on previous year | +309.4% |
| 1944 | 6.13 % change on previous year | -299.8% |
| 1945 | 9.31 % change on previous year | +51.8% |
| 1946 | 1.34 % change on previous year | -85.6% |
| 1947 | 6.27 % change on previous year | +369.1% |
| 1948 | -2.9 % change on previous year | -146.2% |
| 1949 | 4.01 % change on previous year | -238.3% |
| 1950 | 6.93 % change on previous year | +73.0% |
| 1951 | -11.77 % change on previous year | -269.9% |
| 1952 | -13.79 % change on previous year | +17.2% |
| 1953 | -7.22 % change on previous year | -47.6% |
| 1954 | 10.44 % change on previous year | -244.6% |
| 1955 | -0.4929 % change on previous year | -104.7% |
| 1956 | 67.64 % change on previous year | -13823.2% |
| 1957 | 16.13 % change on previous year | -76.2% |
| 1958 | 10.6 % change on previous year | -34.3% |
| 1959 | -9.21 % change on previous year | -186.8% |
| 1960 | 52.36 % change on previous year | -668.8% |
| 1961 | -12.91 % change on previous year | -124.7% |
| 1962 | -4.89 % change on previous year | -62.1% |
| 1963 | 4.22 % change on previous year | -186.3% |
| 1964 | 10.77 % change on previous year | +155.1% |
| 1965 | 0.6978 % change on previous year | -93.5% |
| 1966 | -0.6245 % change on previous year | -189.5% |
| 1967 | 1.96 % change on previous year | -413.5% |
| 1968 | 15.79 % change on previous year | +706.4% |
| 1969 | -8.43 % change on previous year | -153.4% |
| 1970 | 12.75 % change on previous year | -251.3% |
| 1971 | 11.53 % change on previous year | -9.5% |
| 1972 | 14.83 % change on previous year | +28.6% |
| 1973 | 23.55 % change on previous year | +58.8% |
| 1974 | 12.14 % change on previous year | -48.4% |
| 1975 | 15.67 % change on previous year | +29.1% |
| 1976 | 17.02 % change on previous year | +8.6% |
| 1977 | 9.27 % change on previous year | -45.5% |
| 1978 | 0.4178 % change on previous year | -95.5% |
| 1979 | 3.85 % change on previous year | +822.2% |
| 1980 | -14.68 % change on previous year | -481.0% |
| 1981 | -8.11 % change on previous year | -44.8% |
| 1982 | 12.4 % change on previous year | -253.0% |
| 1983 | 20.1 % change on previous year | +62.1% |
| 1984 | 3.26 % change on previous year | -83.8% |
| 1985 | 7 % change on previous year | +114.8% |
| 1986 | -6.02 % change on previous year | -186.0% |
| 1987 | 3.95 % change on previous year | -165.5% |
| 1988 | 0.6497 % change on previous year | -83.5% |
| 1989 | 5.69 % change on previous year | +775.8% |
| 1990 | 9.78 % change on previous year | +71.9% |
| 1991 | -0.3756 % change on previous year | -103.8% |
| 1992 | 0.4795 % change on previous year | -227.7% |
| 1993 | 0.5597 % change on previous year | +16.7% |
| 1994 | 3.18 % change on previous year | +468.1% |
| 1995 | -0.4948 % change on previous year | -115.6% |
| 1996 | 4.03 % change on previous year | -915.2% |
| 1997 | 6.94 % change on previous year | +72.1% |
| 1998 | 3.22 % change on previous year | -53.6% |
| 1999 | 3.66 % change on previous year | +13.7% |
| 2000 | 10.16 % change on previous year | +177.2% |
| 2001 | 5.94 % change on previous year | -41.5% |
| 2002 | 7.74 % change on previous year | +30.3% |
| 2003 | 2.64 % change on previous year | -65.9% |
| 2004 | -0.4914 % change on previous year | -118.6% |
| 2005 | 3.45 % change on previous year | -802.6% |
| 2006 | -5.2 % change on previous year | -250.6% |
| 2007 | -13.26 % change on previous year | +154.9% |
| 2008 | -8.32 % change on previous year | -37.2% |
| 2009 | -8.86 % change on previous year | +6.5% |
| 2010 | -10.77 % change on previous year | +21.5% |
| 2011 | -3.86 % change on previous year | -64.2% |
| 2012 | 3.18 % change on previous year | -182.5% |
| 2013 | 0.8212 % change on previous year | -74.2% |
| 2014 | 5.13 % change on previous year | +524.5% |
| 2015 | -1.52 % change on previous year | -129.6% |
| 2016 | -3.17 % change on previous year | +108.9% |
| 2017 | 1.34 % change on previous year | -142.3% |
| 2018 | -1.59 % change on previous year | -218.5% |
| 2019 | 0.8703 % change on previous year | -154.8% |
| 2020 | -8.05 % change on previous year | -1025.3% |
| 2021 | 2.49 % change on previous year | -130.9% |
| 2022 | 3.51 % change on previous year | +41.1% |
Iran compared with similar countries
- Iran's 3.51 % change on previous year is above the median for upper middle income countries, which is -0.0344 % change on previous year. (57 countries reporting)
- Iran's 3.51 % change on previous year is above the median for Middle East, North Africa, Afghanistan & Pakistan, which is 1.6 % change on previous year, 2.2× the median. (22 countries reporting)
Biggest year-on-year movements
Years where emissions of air pollutants, annual growth rate in Iran changed far more than this series normally does. A large move can be a real event or a change in how the figure was measured — the source note below says who published it.
| Year | Change | From | To |
|---|---|---|---|
| 1956 | +13823.2% | -0.4929 % change on previous year | 67.64 % change on previous year |
| 2020 | -1025.3% | 0.8703 % change on previous year | -8.05 % change on previous year |
| 1996 | +915.2% | -0.4948 % change on previous year | 4.03 % change on previous year |
| 1979 | +822.2% | 0.4178 % change on previous year | 3.85 % change on previous year |
| 2005 | +802.6% | -0.4914 % change on previous year | 3.45 % change on previous year |
| 1989 | +775.8% | 0.6497 % change on previous year | 5.69 % change on previous year |
Averages by decade
| Decade | Average | Lowest | Highest | Years |
|---|---|---|---|---|
| 1750s | 0.1744 % change on previous year | 0.1726 % change on previous year | 0.1761 % change on previous year | 9 |
| 1760s | 0.171 % change on previous year | 0.1687 % change on previous year | 0.1725 % change on previous year | 10 |
| 1770s | 0.1672 % change on previous year | 0.1649 % change on previous year | 0.1689 % change on previous year | 10 |
| 1780s | 0.163 % change on previous year | 0.161 % change on previous year | 0.1648 % change on previous year | 10 |
| 1790s | 0.1583 % change on previous year | 0.1563 % change on previous year | 0.1605 % change on previous year | 10 |
| 1800s | 0.1531 % change on previous year | 0.1507 % change on previous year | 0.1556 % change on previous year | 10 |
| 1810s | 0.1474 % change on previous year | 0.1452 % change on previous year | 0.1504 % change on previous year | 10 |
| 1820s | 0.45 % change on previous year | 0.1446 % change on previous year | 0.4967 % change on previous year | 10 |
| 1830s | 0.4499 % change on previous year | 0.4367 % change on previous year | 0.4685 % change on previous year | 10 |
| 1840s | 0.4157 % change on previous year | 0.4034 % change on previous year | 0.434 % change on previous year | 10 |
| 1850s | 0.321 % change on previous year | 0.2785 % change on previous year | 0.5694 % change on previous year | 10 |
| 1860s | 0.2541 % change on previous year | 0.2365 % change on previous year | 0.2734 % change on previous year | 10 |
| 1870s | 1.03 % change on previous year | 0.2317 % change on previous year | 1.2 % change on previous year | 10 |
| 1880s | 0.958 % change on previous year | 0.8887 % change on previous year | 1.03 % change on previous year | 10 |
| 1890s | 0.6168 % change on previous year | 0.5496 % change on previous year | 0.872 % change on previous year | 10 |
| 1900s | -1.83 % change on previous year | -2.43 % change on previous year | 0.538 % change on previous year | 10 |
| 1910s | -1.79 % change on previous year | -2.53 % change on previous year | -1.41 % change on previous year | 10 |
| 1920s | -2.92 % change on previous year | -4.14 % change on previous year | -2.12 % change on previous year | 10 |
| 1930s | -5.28 % change on previous year | -8.86 % change on previous year | 0.9137 % change on previous year | 10 |
| 1940s | 1.87 % change on previous year | -3.07 % change on previous year | 9.31 % change on previous year | 10 |
| 1950s | 6.93 % change on previous year | -13.79 % change on previous year | 67.64 % change on previous year | 10 |
| 1960s | 5.89 % change on previous year | -12.91 % change on previous year | 52.36 % change on previous year | 10 |
| 1970s | 12.1 % change on previous year | 0.4178 % change on previous year | 23.55 % change on previous year | 10 |
| 1980s | 2.42 % change on previous year | -14.68 % change on previous year | 20.1 % change on previous year | 10 |
| 1990s | 3.1 % change on previous year | -0.4948 % change on previous year | 9.78 % change on previous year | 10 |
| 2000s | -0.62 % change on previous year | -13.26 % change on previous year | 10.16 % change on previous year | 10 |
| 2010s | -0.9554 % change on previous year | -10.77 % change on previous year | 5.13 % change on previous year | 10 |
| 2020s | -0.6864 % change on previous year | -8.05 % change on previous year | 3.51 % change on previous year | 3 |
Countries ranked near Iran
- 19 Antigua and Barbuda 3.65 % change on previous year compare
- 20 Cayman Islands 3.62 % change on previous year compare
- 21 United Arab Emirates 3.58 % change on previous year compare
- 23 Saint Pierre and Miquelon 3.42 % change on previous year compare
- 24 Seychelles 3.37 % change on previous year compare
- 25 Ecuador 3.36 % change on previous year compare
More climate change data for Iran
- Spring temperature anomalies 0.0713 °C (2026)
- Summer temperature anomalies 1.08 °C (2026)
- Temperature anomalies by month 0.2419 °C (2026)
- Share of global CO₂ emissions and population 0.8% (2100)
- Population, total, annual growth rate 0.9283 % change on previous year (2025)
- Population, total, per unit of GDP 0.0003 units per US$ of GDP (2025)
- Urban population, annual growth rate 1.39 % change on previous year (2025)
- Urban population, per unit of GDP 0.0002 units per US$ of GDP (2025)
- Urban population, per capita 0.7738 units per person (2025)
- Precipitation anomalies, annual growth rate -620.65 % change on previous year (2025)
Frequently asked questions
- What is emissions of air pollutants, annual growth rate in Iran?
- Emissions of air pollutants, annual growth rate in Iran was 3.51 % change on previous year in 2022, according to Statizoid (derived).
- What is the highest emissions of air pollutants, annual growth rate recorded in Iran?
- The highest recorded value was 67.64 % change on previous year in 1956.
- What is the lowest emissions of air pollutants, annual growth rate recorded in Iran?
- The lowest recorded value was -14.68 % change on previous year in 1980.
- How does Iran rank for emissions of air pollutants, annual growth rate?
- Iran ranks 22nd out of 219 countries with data for 2022.
- Is emissions of air pollutants, annual growth rate rising or falling in Iran?
- Over the last ten years it is up 10.2%. The long-run trend across the full record is volatile.
- Where does this Iran data come from?
- The figures come from Statizoid (derived), published as part of emissions of air pollutants, annual growth rate. Statizoid updates them automatically from the source API.
Download this data
CSV · JSON — 272 observations, free to reuse under Derived by Statizoid from the sources named on the page.
How this figure is calculated
The year-on-year percentage change in emissions of air pollutants. Computed from consecutive annual observations; years either side of a gap are skipped rather than bridged.
Computed from
- emissions of air pollutants Hoesly et al. (2024) – Community Emissions Data System (CEDS) – with major processing by Our World in Data
Statizoid computes this series; the underlying measurements belong to the publishers named above. The arithmetic is applied to every country and year where both inputs report, and nothing is estimated unless the page says so.
About this data
The year-on-year percentage change in emissions of air pollutants. Computed from consecutive annual observations; years either side of a gap are skipped rather than bridged.