SARS-CoV-2 uzatilishining aksariyati bino ichkarisida sodir bo'ladi, aksariyat qismi koronavirusni o'z ichiga olgan havo zarralarini inhalatsiyalash natijasida. Uyda yoki biznesda virus tarqalishining oldini olishning eng yaxshi usuli bu yuqtirilgan odamlarni uzoqroq tutishdir. Ammo 40% hollarda asemptomatik bo'lgan va asemptomatik odamlar koronavirusni boshqalarga yuqtirishlari mumkin bo'lsa, buni qilish juda qiyin.

Niqoblar virusni atrof-muhitga tarqalishining oldini olish uchun juda yaxshi ish qiladi, ammo agar infektsiyalangan odam bino ichida bo'lsa, muqarrar ravishda ba'zi viruslar havoga chiqib ketadi.

Men Kolorado-Bilder universitetida mexanik muhandislik professliman. Mening ishimning ko'p qismi xonada havodan yuqadigan yuqumli kasalliklarning tarqalishini qanday boshqarish masalalariga bag'ishlangan va men o'zimning universitetim, bolalarim maktablari va hatto Alyaska shtatining qonun chiqaruvchisi tomonidan ushbu vaqt davomida ichki makonni xavfsiz qilish bo'yicha maslahat so'rab murojaat qilganman.

Virus bino ichidagi havoga kirib ketgandan so'ng, sizda ikkita imkoniyat bor: tashqaridan toza havo olib kiring yoki bino ichidagi havodan virusni olib tashlang.

 Agar xonada bir nechta odam bo'lsa, xonadagi barcha havo soati kamida olti marta toza havo bilan almashtirilishi kerak. Getty Images orqali Pico / iStock / Getty Images Plus

Hammasi toza, tashqi havo haqida

Xavfsiz ichki makon doimiy ravishda ko'p miqdordagi tashqi havoga ega bo'lib, ichidagi eskirgan havoni almashtiradi.

Tijorat binolarida tashqi havo odatda isitish, shamollatish va havoni sovutish (HVAC) tizimlaridan olinadi. Uylarda, tashqaridan havo ochiq derazalar va eshiklar orqali kirib boradi, bundan tashqari, turli xil ilmoqlar va uyalar orqali kirib boradi.

Oddiy qilib aytganda, bino ichidagi havo qanchalik toza bo'lsa, shuncha yaxshi bo'ladi. Ushbu havoda olib keling, binoning har qanday ifloslantiruvchi moddasini, virus yoki boshqa biron bir narsa suyultiradi va ichidagi har kimning ta'sirini kamaytiradi. Men kabi atrof-muhit muhandislari havo almashinuvi kursi deb ataladigan o'lchov yordamida bino ichidagi havo qancha miqdorda bo'lishini aniqlaydilar. Bu raqam binoning ichidagi havo bir soat ichida tashqaridan havo bilan almashtirilishini aniqlaydi.

Aniq stavka odamlarning soniga va xonaning kattaligiga bog'liq bo'lsa-da, aksariyat mutaxassislar soatiga oltita havo o'zgarishini 10 futdan 10 futgacha bo'lgan xonada uch-to'rt kishilik odam uchun yaxshi deb bilishadi. Pandemiyada bu ko'rsatkich yuqoriroq bo'lishi kerak, 2016 yildagi bitta tadqiqot shuni ko'rsatadiki, bir soat ichida to'qqiz marta almashinuv kursi Gonkong kasalxonasida SARS, MERS va H1N1 tarqalishini kamaytirdi.

AQShdagi ko'plab binolar, ayniqsa maktablar, tavsiya etilgan shamollatish ko'rsatkichlariga javob bermaydi. Yaxshiyamki, binoga ko'proq havo olish oson bo'lishi mumkin. Deraza va eshiklarni ochiq holda saqlash yaxshi boshlanishdir. Ventilyatorni derazaga shamollatish havo almashinuvini sezilarli darajada oshirishi mumkin. Ishlash oynalari bo'lmagan binolarda siz qancha havo pompalayotganini oshirish uchun mexanik shamollatish tizimini o'zgartirishingiz mumkin. Ammo har qanday xonada, odam qancha ko'p bo'lsa, havo tezroq almashtirilishi kerak.

 Xonadagi havo eskirgan yoki koronavirusni o'z ichiga olgan zarrachalar bilan to'la yoki yo'qligini aniqlash uchun CO2 sathidan foydalanish mumkin. Vudhikul Ocharoen / iStock / Getty Images Plus Getty Images orqali

Havo aylanishini o'lchash uchun CO2 dan foydalanish

Shunday qilib, siz xonada havo almashinuvi etarli ekanligini qanday bilishingiz mumkin? Hisoblash juda qiyin. Ammo yordam berishi mumkin bo'lgan oson proksi mavjud. Har safar siz nafas olayotganda CO2 havoga chiqarasiz. Koronavirus ko'pincha nafas olish, yo'talish yoki gaplashish orqali tarqaladi, shuning uchun siz xona potentsial yuqumli ekshalatlar bilan to'ldirilganligini tekshirish uchun siz CO2 darajasini ishlatishingiz mumkin. Agar sizda toza havo yetarli bo'lsa, CO2 darajasi sizni aniqlashga imkon beradi.

Tashqarida, CO2 darajasi millionga 400 dona (ppm) dan oshadi. Yaxshi havalandırılan bir xonada taxminan 800 ppm CO2 bo'ladi. Bundan yuqoriroq va bu xonani ko'proq shamollatish kerakligi belgisidir.

O'tgan yili Tayvanda tadqiqotchilar Taypey universitetida shamollatishning sil kasalligi tarqalishiga ta'siri haqida xabar berishdi. Maktabdagi ko'p xonalar nomukammal va CO2 darajasi 3000 ppm dan yuqori bo'lgan. Muhandislar havo aylanishini yaxshilaganlarida va CO2 miqdorini 600 ppm / s ga oshirganda, avj olish butunlay to'xtadi. Tadqiqotga ko'ra, shamollatishning ko'payishi transmisyonning 97% pasayishiga sabab bo'lgan.

Koronavirus havo orqali tarqalib ketganligi sababli, xonada CO2 darajasi yuqori bo'lishi, agar yuqtirgan odam ichkarida bo'lsa, yuqtirish ehtimoli ko'proq ekanligini anglatadi. Yuqoridagi tadqiqotga asoslanib, men CO2 miqdorini 600 ppm dan pastroq darajada saqlashga harakat qilaman. Yaxshi CO2 hisoblagichlarini 100 dollar atrofida onlayn sotib olishingiz mumkin; shunchaki ularning 50 daqiqada aniqligiga ishonch hosil qiling.

Havo tozalagichlar

Agar siz suyultirish uchun tashqi havo yetarli bo'lmaydigan xonada bo'lsangiz, havoni tozalagichni ham ko'rib chiqing. Ushbu mashinalar zarralarni havodan olib tashlaydi, odatda mahkam to'qilgan tolalardan filtr yordamida. Ular bakteriya va viruslarni o'z ichiga olgan zarralarni ushlab olishlari mumkin va mumkin.

Amerikalik professor Shelli Miller "eng yaxshi" mashq qilish va birinchi navbatda nimalarga elektron ravishda murojaat qilish kerakligi haqida "Suhbat"  «Conversation»  (https://theconversation.com/how-to-use-ventilation-and-air-filtration-to-prevent-the-spread-of-coronavirus-indoors-143732)  nashri so'zlab berdi:

Jahongirxon Abrorov,

O‘zbekiston musulmonlari idorasi

Samarqand viloyat vakilligi matbuot xizmat xodimi ingiliz tilidan tarjima qilindi

How to use ventilation and air filtration to prevent the spread of coronavirus indoors

The vast majority of SARS-CoV-2 transmission occurs indoors, most of it from the inhalation of airborne particles that contain the coronavirus. The best way to prevent the virus from spreading in a home or business would be to simply keep infected people away. But this is hard to do when an estimated 40% of cases are asymptomatic and asymptomatic people can still spread the coronavirus to others.

Masks do a decent job at keeping the virus from spreading into the environment, but if an infected person is inside a building, inevitably some virus will escape into the air.

I am a professor of mechanical engineering at the University of Colorado Boulder. Much of my work has focused on how to control the transmission of airborne infectious diseases indoors, and I’ve been asked by my own university, my kids’ schools and even the Alaska State Legislature for advice on how to make indoor spaces safe during this pandemic.

Once the virus escapes into the air inside a building, you have two options: bring in fresh air from outside or remove the virus from the air inside the building.

 All of the air in a room should be replaced with fresh, outside air at least six times per hour if there are a few people inside.Pico/iStock/Getty Images Plus via Getty Images

It’s all about fresh, outside air

The safest indoor space is one that constantly has lots of outside air replacing the stale air inside.

In commercial buildings, outside air is usually pumped inthrough heating, ventilating and air-conditioning (HVAC) systems. In homes, outside air gets in through open windows and doors, in addition to seeping in through various nooks and crannies.

Simply put, the more fresh, outside air inside a building, the better. Bringing in this air dilutes any contaminant in a building, whether a virus or a something else, and reduces the exposure of anyone inside. Environmental engineers like me quantify how much outside air is getting into a building using a measure called the air exchange rate. This number quantifies the number of times the air inside a building gets replaced with air from outside in an hour.

While the exact rate depends on the number of people and size of the room, most experts consider roughly six air changes an hour to be good for a 10-foot-by-10-foot room with three to four people in it. In a pandemic this should be higher, with one study from 2016 suggesting that an exchange rate of nine times per hour reduced the spread of SARS, MERS and H1N1 in a Hong Kong hospital.

Many buildings in the U.S., especially schools, do not meet recommended ventilation rates. Thankfully, it can be pretty easy to get more outside air into a building. Keeping windows and doors open is a good start. Putting a box fan in a window blowing out can greatly increase air exchange too. In buildings that don’t have operable windows, you can change the mechanical ventilation system to increase how much air it is pumping. But in any room, the more people inside, the faster the air should be replaced.

 CO2 levels can be used to estimate whether the air in a room is stale and potentially full of particles containing the coronavirus. Vudhikul Ocharoen/iStock/Getty Images Plus via Getty Images

Using CO2 to measure air circulation

So how do you know if the room you’re in has enough air exchange? It’s actually a pretty hard number to calculate. But there’s an easy-to-measure proxy that can help. Every time you exhale, you release CO2into the air. Since the coronavirus is most often spread by breathing, coughing or talking, you can use CO2 levels to see if the room is filling up with potentially infectious exhalations. The CO2 level lets you estimate if enough fresh outside air is getting in.

Outdoors, CO2 levels are just above 400 parts per million (ppm). A well ventilated room will have around 800 ppm of CO2. Any higher than that and it is a sign the room might need more ventilation.

Last year, researchers in Taiwan reported on the effect of ventilation on a tuberculosis outbreak at Taipei University. Many of the rooms in the school were underventilated and had CO2 levels above 3,000 ppm. When engineers improved air circulation and got CO2 levels under 600 ppm, the outbreak completely stopped. According to the research, the increase in ventilation was responsible for 97% of the decrease in transmission.

Since the coronavirus is spread through the air, higher CO2 levels in a room likely mean there is a higher chance of transmission if an infected person is inside. Based on the study above, I recommend trying to keep the CO2 levels below 600 ppm. You can buy good CO2 meters for around $100 online; just make sure that they are accurate to within 50 ppm.

Air cleaners

If you are in a room that can’t get enough outside air for dilution, consider an air cleaner, also commonly called air purifiers. These machines remove particles from the air, usually using a filtermade of tightly woven fibers. They can capture particles containing bacteria and viruses and can

American professor Shelley Miller talks about how to do this and what to look for first, at Conversation (https://theconversation.com/how-to-use-ventilation-and-air-filtration-to-prevent-the-spread- of-coronavirus-indoors-143732) told:

 Jahongirxon Abrorov,

Office of Muslims of Uzbekistan

The press service of the Samarkand regional representative office translated from English