To collect a sample of acid rain, acid rain can not be, because there are dozens of rain a year, some rain may be acid rain, a rain might not rain, it depends on annual average.
Currently defined scientific standard of acid rain is still under discussion, but it is generally believed: the average annual precipitation pH values higher than 5.65, acid rain rate is 0-20%, non-acid rain; at 5.30 pH value - between 5.60 Acid rain rate is 10 - 40%, mild acid rain; pH value of 5.00 - 5.30 between acid rain rate is 30-60%, moderate acid rain; pH value of 4.70 - 5.00 between acid rain rate is 50-80% heavier acid rain; pH value of less than 4.70, acid rain rate is 70-100% for heavy acid rain area.
This is called the five criteria. In fact, the city Beijing, Xining, Lanzhou, Urumqi, also collected several acid rain, but the annual rate of pH and acid rain, acid rain in the area of non-standard, it is a non-acid rain.
China's three major acid rain areas include:
1. Southwest acid rain: precipitation in the region is a serious acid rain pollution after the Central District.
2. Central acid rain area: Currently, it has become the country's largest range of acid rain pollution, acid rain, polluted centers highest intensity.
3. Acid rain in east coastal area: its pollution intensity lower than central, southwest of acid rain area.
Including the world's three major acid rain:
1, acid rain in North America
2, Western Europe, acid rain
3, acid rain area southwest China |