AIRLINK 76.15 Increased By ▲ 1.75 (2.35%)
BOP 4.86 Decreased By ▼ -0.09 (-1.82%)
CNERGY 4.31 Decreased By ▼ -0.03 (-0.69%)
DFML 46.65 Increased By ▲ 1.92 (4.29%)
DGKC 89.25 Increased By ▲ 1.98 (2.27%)
FCCL 23.48 Increased By ▲ 0.58 (2.53%)
FFBL 33.36 Increased By ▲ 1.71 (5.4%)
FFL 9.35 Decreased By ▼ -0.01 (-0.11%)
GGL 10.10 No Change ▼ 0.00 (0%)
HASCOL 6.66 Decreased By ▼ -0.11 (-1.62%)
HBL 113.77 Increased By ▲ 0.17 (0.15%)
HUBC 143.90 Increased By ▲ 3.75 (2.68%)
HUMNL 11.85 Decreased By ▼ -0.06 (-0.5%)
KEL 4.99 Increased By ▲ 0.12 (2.46%)
KOSM 4.40 No Change ▼ 0.00 (0%)
MLCF 38.50 Increased By ▲ 0.10 (0.26%)
OGDC 133.70 Increased By ▲ 0.90 (0.68%)
PAEL 25.39 Increased By ▲ 0.94 (3.84%)
PIBTL 6.75 Increased By ▲ 0.22 (3.37%)
PPL 120.01 Increased By ▲ 0.37 (0.31%)
PRL 26.16 Increased By ▲ 0.28 (1.08%)
PTC 13.89 Increased By ▲ 0.14 (1.02%)
SEARL 57.50 Increased By ▲ 0.25 (0.44%)
SNGP 66.30 Decreased By ▼ -0.10 (-0.15%)
SSGC 10.10 Decreased By ▼ -0.05 (-0.49%)
TELE 8.10 Increased By ▲ 0.15 (1.89%)
TPLP 10.61 Decreased By ▼ -0.03 (-0.28%)
TRG 62.80 Increased By ▲ 1.14 (1.85%)
UNITY 26.95 Increased By ▲ 0.32 (1.2%)
WTL 1.34 Decreased By ▼ -0.02 (-1.47%)
BR100 7,957 Increased By 122.2 (1.56%)
BR30 25,700 Increased By 369.8 (1.46%)
KSE100 75,878 Increased By 1000.4 (1.34%)
KSE30 24,343 Increased By 355.2 (1.48%)

A warming planet means more hot days than before, and the phenomenon could cause three to nine more days per year when ozone levels are unhealthy by the 2050s, scientists warned on Thursday.
Automobile exhaust spews nitrogen dioxide and causes a build-up of unhealthy ground level ozone in the atmosphere. The problem tends to get worse when the temperature rises and the air stagnates. The dangers of ozone pollution can include lung damage in adults and asthma in small children.
"In the coming decades, global climate change will likely cause more heat waves during the summer, which in turn could cause a 70 to 100 percent increase in ozone episodes, depending on the region," said Lu Shen, a graduate student at the Harvard John A. Paulson School of Engineering and Applied Sciences and lead author of the study in Geophysical Research Letters.
California, the south-western United States and the north-east region could see up to nine more days of dangerous ozone levels than present, the study found.
Much of the rest of the United States will likely experience an increase of 2.3 days, according to the model devised by researchers, based on observed relationships between temperature and ozone to predict future episodes.
"Typically, when the temperature increases, so does surface ozone," said co-author Loretta Mickley.
"Ozone production accelerates at high temperatures, and emissions of the natural components of ozone increase. High temperatures are also accompanied by weak winds, causing the atmosphere to stagnate. So the air just cooks and ozone levels can build up."
High ozone spells danger for people who have chronic lung disease. They are often warned to stay inside on unhealthy ozone days.
Unhealthy ozone levels range from 100 to 500 parts per billion, according to the US Environmental Protection Agency.
Ways to reduce ozone pollution include driving less and cutting down on electricity use, the EPA says.
"This research gives us a much better understanding of how ozone and temperature are related and how that will affect future air quality," said Mickley.
"These results show that we need ambitious emissions controls to offset the potential of more than a week of additional days with unhealthy ozone levels."

Copyright Agence France-Presse, 2016

Comments

Comments are closed.