Efterhånden som skovbrande bliver værre, røg spreder sig, vækker sundhedsmæssige bekymringer

Først kom flammerne, en rasende ildstorm drevet af vindstød på 50 km / t, der forbrændte Kelsey Nortons hus og dræbte 85 mennesker i hendes samfund.

Så kom røgen – ikke bare fra skoven, men også fra omkring 14, 000 huse og deres indhold, der brændte, genererede en tyk fane, der omsluttede dele af det nordlige Californien i ugevis og fik Norton til at gispe.

Og siden branden, mere end et år nu, det har været sygdom:gentagne luftvejsinfektioner, der undergraver Nortons styrke, blande sig i hendes arbejde og efterlade den 30-årige hjertesygeplejerske bekymret for fremtidige helbredsproblemer.

"Jeg vil ikke have kræft i 50'erne, fordi jeg inhalerede røg i 30'erne, " hun sagde.

Det øjeblikkelige antal liv og ejendom, der gik tabt, da en brand rev gennem Sierra Nevada-byen Paradise ved foden af ​​bjergene, Californien i november 2018 er veldokumenteret. Stadig ukendt er den langsigtede virkning af den intense røgeksponering, som tragediens overlevende og de hundredtusindvis af mennesker, der bor i lokalsamfundene, har lidt under vinden af ​​flammen.

Stadig mere intense naturbrande brænder skove fra hele det vestlige USA til Australien og vækker bekymring blandt beboere og sundhedspersonale om langsigtede helbredspåvirkninger fra røgeksponering.

Problemet har vidtrækkende konsekvenser, da klimaændringer gør nogle områder af kloden tørrere og mere tilbøjelige til brande, der sender røgfaner op, som kan rejse tusindvis af kilometer og påvirke millioner af mennesker.

De hidtil usete brande, der brænder over Australien, er det seneste eksempel, da de dækker større byer med farlig luftforurening. Røg fra disse brande, som begyndte at brænde i september, i denne uge havde spredt sig over mere end 7,7 millioner kvadrat miles (20 millioner kvadratkilometer) og drevet over Stillehavet for at nå Sydamerika, ifølge FN's meteorologiske agentur og Copernicus Atmosphere Monitoring Service.

Brandene har udbrudt mere end 2, 000 huse og dræbte mindst 26 mennesker. Myndighederne beordrede nye evakueringer i New South Wales og nabostaten Victoria, da stigende temperaturer og uregelmæssige vinde fredag ​​truede med at ventilere snesevis af flammer, der stadig brænder uden kontrol.

Begge stater udstedte advarsler om farlig luftkvalitet for berørte områder og sagde, at folk med helbredsproblemer burde overveje at flytte, indtil røgen forsvinder.

Forener faren, eksperter og brandmænd siger, er udbredelsen af ​​byggematerialer og husholdningsartikler fremstillet af petroleumsbaseret plast, lige fra VVS-rør til udvendig sidebeklædning. De brænder varmere og genererer røg, der er mere giftig end træ gør, udsætter mennesker for adskillige farlige kemikalier.

Forskere og sundhedsembedsmænd er overbeviste om, at flere mennesker vil blive syge, og mange vil dø, efterhånden som regioner som vesten i USA ser større, mere intense skovbrande.

Anslået 20, 000 for tidlige dødsfald sker nu årligt i USA på grund af kronisk røgeksponering for naturbrande. Det forventes at fordobles i slutningen af ​​århundredet, ifølge forskere finansieret af NASA, da titusindvis af millioner mennesker bliver udsat for massive "røgbølger", der kommer fra flammer i vestlige stater.

Men selvom disse prognoser hjælper med at illustrere de dybtgående virkninger af et opvarmende klima, de kan ikke forudsige, hvilke brande der vil vise sig dødelige, og hvilke personer der vil udvikle lungesygdomme eller andre sygdomme.

En af relativt få langsigtede undersøgelser af spørgsmålet er undervejs på California National Primate Research Center. Halvtreds rhesusaber, der lever i udendørs kugler året rundt, blev udsat for en længere periode med ild i røg som spædbørn i 2008. De har udviklet lunger 20% mindre end en anden gruppe aber født et år senere, fandt forskere.

"Det er den dyremodel, der er tættest på at replikere, hvad der sker med børn, " sagde Lisa Miller, centrets associerede forskningsdirektør.

Forskellen viste sig først, da dyrene var teenagere, og er fortsat, mens de er blevet modne. Det er umuligt for det utrænede øje at skelne de røgudsatte aber fra hundredvis af andre, der deler deres kuglepenne, men Millers team planlægger derefter at undersøge, hvordan den nedsatte lungefunktion påvirker abernes aktivitetsniveau.

Når dyrene bliver ældre, enhver sygdom, de udvikler, og hvordan de dør, ville give fingerpeg om skæbnen for mennesker, der er stærkt udsat for røg.

Undersøgelser af vilde brandmænd giver også indsigt i risikoen ved røginhalering. De har vist betydeligt højere lungekræft og dødsfald som følge af hjertesygdomme, sagde Michael Kleinman, der forsker i sundhedsvirkningerne af luftforurening og er professor i miljøtoksikologi ved University of California, Irvine.

Firefighters get much higher and more frequent doses of smoke, but Kleinman said a proportional increase in illnesses could be expected among the general public exposed to wildfire smoke across California and the West.

"It's safe to say there will probably more effects at the long-term level, " Kleinman said. "Especially if those events happened over a longer period of time or more repeatedly, there will be cumulative damage to the lung and heart which eventually will lead to chronic disease."

As she fled with her boyfriend ahead of the fire that destroyed Paradise on the morning of Nov. 8, 2018, Norton said the smoke was so thick "it was like midnight."

A few days later, she went back to work at a hospital in Chico, about 15 miles (24 kilometers) miles from Paradise. But smoke from the still-burning fire had made it inside the facility.

There weren't enough face masks to go around so Norton said she went without one for several days.

Initially she felt just a bit wheezy, as she had during the last major fire in the area about a decade earlier. But two weeks later she came down with a respiratory infection that brought fever and severe congestion.

When that finally cleared, she got another, then another—eight or nine infections in all over the past year.

"I just want to break this cycle of sickness, " hun sagde.

Norton says she never smoked, nor did her parents, and never had any respiratory issues prior to the fire. She missed so much work in the months after the fire that she got a warning from a supervisor.

To try to keep from getting sick, she rinses out her sinuses regularly and takes antihistamines to reduce inflammation in her airways. She also avoids large gatherings, including skipping office parties and two weddings, out of fear that she could pick up a virus. She tries to eat healthy and reduce stress by seeing a counselor.

Norton has been to a pulmonologist and two ear nose and throat doctors to little avail, and has been referred to a sinus specialist at Stanford University for further testing.

The pulmonologist who initially treated her, Dinesh Verma, said he sees a "direct correlation" between Norton's smoke exposure and her subsequent health struggles.

"The logical explanation definitely would be that intense smoke, basically chemical exposure, did damage the airways to the extent that they're now more susceptible" to infection, Verma said.

Verma said virtually all of his hundreds of patients from Chico and Paradise had complications after the fire that required them to be hospitalized or treated.

Most had preexisting conditions such as asthma and needed only a trigger to send them into a downward spiral. Predicting what will happen with otherwise-healthy patients like Norton is more difficult, han sagde.

Norton is among about 9, 000 people who responded to a health survey as part of a long-term health study of smoke exposure in Paradise and other California communities. The work is led by researchers at the University of California, Davis, who plan to track the lung health of a small number of those respondents in coming years by measuring their breathing capacity.

They're also collaborating with Williams at the primate center to see if the decline seen in the rhesus monkeys has parallels for human infants.

Dr. Nicholas Kenyon, a pulmonologist involved in the effort, said determining the health effects of smoke is increasingly urgent given the region's burgeoning population and more frequent fires due to climate change.

"We've got the population affected right now, but it's not going to be isolated to us. This is going to be the entire West, " Kenyon said. "Nobody's been really inhaling this kind of stuff from structures until now."

Another participant in the UC Davis study, 64-year-old Elizabeth Watling, lives in Chico and remained there through the fire so she could look after her 94-year-old aunt. She recalls smoke so thick that it left a layer of ash all over town, gray and light as snow. The air remained heavily polluted until it rained more than two weeks later.

When she gardens or does other outdoor activities, Watling wears a mask because her throat has become so easily irritated by dust. She fiddles with it often, taking the mask on and off to talk, and wonders how effective it will be since she can fit her fingers through gaps along her cheeks.

The health issues Watling blames on the smoke are less severe than Norton's—a scratchy throat that won't go away, coughs that linger, shortness of breath.

She expected those to go away but they haven't. Watling now figures that, given her age, she won't ever fully recover and the smoke could shave years off her life.

"I don't think the news is good for me, " hun sagde.

© 2020 The Associated Press. Alle rettigheder forbeholdes.