Today we review research into recent global estimates of PM2.5 using space based sensors. Over the last decade, a trend toward worsening conditions in South and East Asia (with 51% more of the population exposed to pollution above WHO guidelines rose to 70%) and slightly improved conditions in the eastern USA and Canada (where the exposed population declined from 62% to 19%) was estimated from these satellite observations at a 10 km resolution. The authors expect in future that similar estimates may be made of NO2 concentrations at an improved resolution which may be more helpful in pin pointing urban pollution conditions and their sources.
Key Quotes:
“More than 3 million people died prematurely in 2010 due to ambient exposure to fine particulate matter (PM2.5), according to estimates from the Global Burden of Disease Study”
“We found notable trends of increasing PM2.5 in South and East Asia, where billions of people live. Meanwhile, parts of North America are getting cleaner,”
“In a sense, the satellites we use are little more than extremely well calibrated cameras that take pictures of the earth below. When aerosol particles are present, these pictures begin to look a little hazy,”
“The researchers used AOD data …to estimate ground-level PM2.5 at a spatial resolution of approximately 10 km × 10 km. Although some regions experienced a decrease in PM2.5 over the period 1998–2012, the global population-weighted average increased by an estimated 2.1% per year. Rising levels of air pollution in developing regions in South and East Asia largely drove the upward trend”
“researchers estimated that the proportion of people in South and East Asia exposed to PM2.5 at levels exceeding the World Health Organization (WHO) interim target of 35 μg/m3 rose from 51% in 1998–2000 to 70% in 2010–2012. In contrast, the proportion of North Americans exposed to PM2.5 at levels above the WHO air quality guideline of 10 μg/ m3 fell from 62% in 1998–2000 to 19% in 2010-12”
“Satellite-based estimates reported here will enable researchers to design and conduct large epidemiological studies in low- and middle-income countries that lack the extensive ground monitoring networks found in higher income countries,”
“In the future, we hope to infer global PM2.5 data at a higher spatial resolution and to investigate other air pollution compounds, such as nitrogen dioxide, using satellite data,”
