Intense heatwaves exacerbating air quality issues worldwide, new WMO report finds

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A recently released report by the World Meteorological Organization (WMO) has shed light on the escalating frequency and intensity of heatwaves, which are significantly deteriorating air quality across the globe. This worsening air quality is driven by a combination of factors, including wildfires and desert dust intrusions, highlighting the complex interplay between climate and air quality.

The 2023 WMO Air Quality and Climate Bulletin, the third in an annual series, underlines that it's not just the soaring temperatures during heatwaves that pose a threat; rather, it's the often-overlooked pollution consequences that carry profound implications for human health and the environment.

Two noteworthy incidents in 2022 serve as prime examples:

US and European Heatwaves: Heatwaves in the United States and Europe ignited devastating wildfires and ushered in desert dust intrusions, resulting in hazardous air quality. These events had dire consequences for human health and the ecosystem.

Fossil Fuel Emissions: The report draws attention to the connection between fossil fuel combustion and air quality. Emissions like carbon dioxide (CO2) and nitrogen oxide (NO) can give rise to aerosols, major contributors to particulate matter (PM) pollution. The blistering European heatwave of 2022, the hottest on record, led to heightened levels of PM and ground-level ozone.

During this period, several European air quality monitoring stations exceeded the World Health Organization's recommended ozone air quality guideline of 100 ug/cum (micrograms per cubic meter) for an 8-hour exposure.

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Moreover, an extraordinary desert dust intrusion over the Mediterranean and Europe in August 2022, compounded by elevated temperatures, had detrimental impacts on human health. Ground-level ozone, known for shielding the Earth from harmful ultraviolet rays in the stratosphere, became harmful when concentrated closer to the surface. It also significantly hampered staple food crop yields, with wheat and soybean losses reaching staggering levels of 15-30% in vital agricultural regions of India and China.

Heatwaves and arid conditions, often accompanying wildfires, further exacerbate the problem. Wildfires release aerosols into the atmosphere, amplifying air pollution. A prolonged heatwave in September 2022 in the northwestern United States correlated with an upsurge in biomass burning, leading to compromised air quality throughout the region, as reported by the US Environmental Protection Agency (EPA).

These wildfires were also identified as major contributors to nitrogen deposition in various natural ecosystems, impacting biodiversity, clean drinking water sources, and air quality.

While the WMO's bulletin reflects the situation in 2022, it is crucial to note that 2023 has witnessed even more extreme conditions. WMO Secretary-General Petteri Taalas stressed the urgency of the matter, noting that July 2023 was the hottest month on record, with unrelenting heatwaves causing catastrophic wildfires in Canada, Hawaii, and the Mediterranean region. These events have resulted in perilous air quality conditions for millions and sent smoke plumes across the Atlantic and into the Arctic.

Taalas underscored the inseparable link between climate change and air quality, emphasizing the need for a holistic approach to address both challenges and break this detrimental cycle.

The release of the WMO report coincides with the International Day of Clean Air for blue skies, observed on September 7, with this year's theme being "Together for Clean Air." (Agencies)