In June 2023, New York City experienced an unexpected drop in temperature, even though the sun was blazing. A recent study revealed that smoke and dust clouds from wildfires in nearby Canada blocked sunlight from reaching the ground, reducing the city’s temperature by 3°C. The phenomenon, where less sunlight and warmth reach the Earth’s surface, is known as Global Dimming. Scientists say this is a sign of climate change impact. The findings were published in the Nature Communications Earth & Environment Journal. Researchers from Rutgers Health Institute noted that toxic gases trapped in the atmosphere contributed to this rare climate event.

The research team, led by Philip Demokrito and Georgios Kelisidis, studied how smoke and dust from Canada’s wildfires traveled over 1,000 kilometers, covering cities like New York and New Jersey. Due to yellow-colored organic carbon molecules in the dust, sunlight couldn’t penetrate through, causing the temperature drop. This thick “smoke umbrella” also disrupted normal wind flow, leading to severe air pollution. Fine particulate matter (PM2.5) in New York’s atmosphere rose to three times the recommended level by the U.S. Environmental Protection Agency and eight times the safe limit suggested by the World Health Organization.

Due to the excessive air pollution, residents began facing respiratory issues. Another Rutgers study published in Environmental Science & Technology Journal found that each person in New York inhaled about 9.3 mg of smoke particles, reducing their immune response against infections by 50%. Government data also confirmed that asthma-related cases surged from 44% to 82% during the wildfire period. Researcher Philip Demokrito warned that this was the first such incident in the area, but not the last. Due to ongoing climate change, frequent wildfires in Northeast America may continue to worsen pollution and public health risks in urban regions.