Global Air Pollution and Intercontinental Transport

This page last reviewed October 14, 2016

Global Air Pollution and its Effects on California


-- Global pollution effects in California are most noticeable in clean air areas; high pollution days in California are due to local sources

-- Asian pollution sources may slow future progress toward clean air in California

-- Large dust storms from Asia's deserts hit California a few times a decade.

-- Dilute amounts of dust from Asia's deserts regularly cross the Pacific to California.

-- Smoke from biomass burning in southeast Asia and wildfires in Siberia can also reach California.

-- Asia's coal smoke, vehicle exhaust, toxics, and farm and road dust also regularly cross the Pacific

-- Ozone from Asia's cities adds to natural " background " ozone in clean air areas of California.

-- Economic growth in Asia will increase emissions and pollution impacts in California.  Pollution controls may slow emission growth

-- Climate change may facilitate pollutant movement and ozone formation, enhancing the effects of Asian pollution in California


View Slides Presented at the ARB Board Meeting on 1/22/2004

Overview Of Global Air Pollution:

Severe air pollution is commonly associated with population centers, areas of concentrated industry or other human activities, but air pollution does not respect economic or political boundaries as it spreads downwind.  Minute concentrations of air pollutants are found all over the world.  Even modest levels of industrial activity can pollute large areas of the Earth.  For example, lead emitted from metal smelting in Europe during the Greek and Roman empires deposited trace concentrations in Greenland that have been found in ice cores.

The global spread of pollution can be seen in Figure 1, which shows the planetary distribution of carbon monoxide produced by burning fossil fuels or vegetation, as measured by satellite in 2000.


Carbon monoxide is accompanied by other combustion-related pollutants, such as smoke, soot, sulfates, and toxic materials.  Present global levels of population, urban and industrial development, and vegetation burning are causing rising concentrations of air pollution to be spread throughout the Northern Hemisphere. 


Particulate Air Polution:

The global atmospheric particle load comes from a mix of natural and human sources.  Dust from Earth's great deserts mixes with dust from roads, farms, and other soil disturbance.  Smoke from wildfires mixes with smoke from burning forests and grasslands as well as coal and oil. 

Global Particulate Air pollution and its Effects on California

Atmospheric Ozone  

Ozone due to manmade pollution is the main irritant in "smog" but it is also a natural component of the atmosphere.  Understanding the effects of global pollution on local ozone exposure requires tracking ozone from both natural and manmade sources.

Global Ozone and its Effects on Califorina


If you have any questions or comments about the content of the
Intercontinental Transport web pages, please contact
Ash Lashgari at (916) 323-1506 .