Ua hoʻopuka ka World Health Organization (WHO) i kahi hōʻike i ka pule i hala e hōʻike ana he ʻoi aku ma mua o 1 miliona mau make mai ka maʻi pneumonia, ka hānō, ka maʻi maʻi ʻōpū a me nā maʻi ʻē aʻe e hiki ke pale ʻia i ka honua holoʻokoʻa i kēlā me kēia makahiki inā hana nā ʻāina i nā hana e hoʻomaikaʻi ai i ka maikaʻi o ka ea. ʻO kēia ka noiʻi nui mua loa o ke kino honua no ka hoʻohaumia ʻana o ka ea o waho mai ka honua holoʻokoʻa.
ʻOiai ʻaʻole hoʻohālikelike ka pollution ea US i ka mea i loaʻa ma nā ʻāina e like me Iran, India, a me Pakistan, ʻaʻole liʻiliʻi e hoʻolauleʻa i ka nānā ʻana i nā helu no Kaleponi.
Ke hilinaʻi nei ka noiʻi ʻana i ka ʻikepili i hōʻike ʻia e ka ʻāina i nā makahiki i hala iho nei, a e ana i nā pae o nā ʻāpana ea i ka liʻiliʻi ma mua o 10 micrometers - i kapa ʻia ʻo PM10s - no kahi kokoke i 1,100 mau kūlanakauhale. Ua hoʻokuʻu ʻo WHO i kahi papaʻaina pōkole e hoʻohālikelike ana i nā pae o nā ʻāpana lepo ʻoi aku ka maikaʻi, i kapa ʻia ʻo PM2.5s.
Manaʻo ʻo WHO i ka palena kiʻekiʻe o 20 micrograms i kēlā me kēia cubic meter no PM10s (i wehewehe ʻia ʻo ka "mean makahiki" ma ka hōʻike WHO), hiki ke hoʻopilikia i nā pilikia hanu i nā kānaka. ʻOi aku ma mua o 10 micrograms no ka cubic mika o PM2.5s i manaʻo ʻia he mea pōʻino i ke kanaka.
ʻO Bakersfield ke poʻo o ka papa inoa o nā kūlanakauhale ʻino loa o ka lāhui no ka hoʻonui ʻia ʻana o ka ʻike ʻana i nā ʻāpana ʻelua o nā mea ʻeleʻele, a loaʻa iā ia ka mean makahiki o 38ug/m3 no PM10s, a me 22.5ug/m3 no PM2.5s. ʻAʻole mamao loa ʻo Fresno, e lawe ana i ka 2nd wahi ma ka ʻāina holoʻokoʻa, me Riverside/San Bernardino e koi ana i ka 3rd wahi ma ka papa inoa US. Ma ke ʻano holoʻokoʻa, ua ʻōlelo nā kūlanakauhale ʻo Kaleponi i ka 11 o ka 20 kiʻekiʻe loa o ka poʻe lawehala ma nā ʻano ʻelua, ʻo ia mau mea a pau ma mua o ka paepae palekana WHO.
"Hiki iā mākou ke pale i kēlā mau make," wahi a Kauka Maria Neira, ka luna hoʻomalu o ke keʻena olakino a me ke kaiapuni o WHO, nāna i ʻike i nā hoʻopukapuka no ka haʻahaʻa haʻahaʻa haʻahaʻa e uku koke ʻia ma muli o ka haʻahaʻa o ka maʻi a no laila, haʻahaʻa nā kumukūʻai olakino.
No nā makahiki, ua hoʻopili nā mea noiʻi ma ka honua holoʻokoʻa i nā pae haʻahaʻa haʻahaʻa i nā ululāʻau kūlanakauhale olakino. Hōʻike nā haʻawina i mālama ʻia e ka Natural Environments Research Council i ka makahiki 2007 e hiki ke hoʻokō ʻia ka hoʻemi ʻana o PM10 o 7%-20% inā he nui nā kumu lāʻau i kanu ʻia, ma muli o ka loaʻa ʻana o nā wahi kanu kūpono. Ma ʻAmelika Hui Pū ʻIa, ua paʻi ka Center for Urban Forestry Research i kahi pepa i ka makahiki 2006 e hōʻike ana i ka kānana ʻeono miliona lāʻau o Sacramento i 748 tons o PM10 i kēlā me kēia makahiki.