タイの涼しく霞んだ朝は例年多くの住民に歓迎されますが、最近、バンコクなどの大都市では不芳な原因で空気が霞んでいます。その原因とは、人体へ容易に入り込んで健康に悪影響を及ぼす非常に小さな粒子であり、住民の多くはPM2.5など大気汚染の状況を示す数値に大きな関心を持っています。バンコクなどの大気汚染レベルは2019年1月の2週目から悪化しています。PM2.5の濃度はバンコクおよびその周辺地域で警戒レベルに達しており、2018年より状況は悪化しています。専門家によれば、大気汚染の主な原因としてタイ国内および近隣国におけるディーゼルエンジンの排気ガス、バイオマスの燃焼、工場からの排気などが挙げられています。また、11月~5月頃まで続く乾季は雨が降らず空気がよどむため、大気汚染が発生しやすくなります。
大気汚染はタイに限らずミャンマー、ラオス、カンボジアなどASEAN諸国でも問題になっています。これはAsean Agreement on Transboundary Haze Pollution (AATHP) が推し進める単式農法や森林破壊の防止活動が機能していないことも一因と考えられます。
PM2.5とは
PM2.5は大気中に浮遊している2.5μm以下の小さな粒子です。その大きさは細菌とほぼ同じであり、髪の毛の平均的な太さ(50μm)の1/25程度しかないため、鼻毛による遮断効果は期待できず鼻や口から容易に肺へ侵入します。PM2.5は大気中に長く滞留し長距離を移動するため、中国、米国、欧州でも問題視されています。PM2.5にはディーゼルエンジンの排気ガスやバイオマスの燃焼によって排出されるものや、ガス状の汚染物質が大気中で化学反応により粒子化したものがあります。
PM2.5の環境基準
PM2.5は肺や血液中に侵入し、人間の健康に影響をもたらします。PM2.5は呼吸器系疾患、心血管系疾患、がんなど死に至る疾病を引き起こすことが指摘されており、特に子供や老人、妊婦に与える影響が大きいと考えられています。また、長期間、高濃度のPM2.5に曝されると、高血圧や生殖系への影響が生じる可能性があります。
タイの環境基準では、PM2.5の濃度について1日平均50μg/m3以下と設定されています。これはWHOが定める25μg/m3、日本、アメリカの基準である35μg/m3を上回っています。
参考まで、右の表にPM2.5の年平均濃度に対する各国の環境基準を示します。
対策
タイの公害管理局(PCD: Pollution Control Department)は、ディーゼル車の使用制限、屋外での焚き火の禁止、自家用車の使用抑制などを呼びかけていますが、これらの対策は即時的な効果を期待できません。
大気汚染は温度や風速といった気象条件や降雨に大きな影響を受けます。一般的に温度が高い方が汚染物質の拡散が促進されることが知られています。また、降雨によって汚染物質の一部が除去されます。ある調査結果では、1時間の降雨によりPM2.5の濃度が56.3%低下し、その効果が12時間持続することが明らかになっており、PCDは人工降雨による汚染物質の除去も試みています。
個人で出来る最も身近な対策はPM2.5に対応するN95マスクの着用です。また、室内への汚染物質の侵入を防ぐためのフィルターや空気清浄機も効果が期待できます。
PM2.5濃度の確認方法
PM2.5のリアルタイム濃度は以下のアプリケーションやウェブサイトで確認することができます。
-Air4thai (application)
-AirVisual (application)
-http://air4thai.pcd.go.th/webV2/
-https://aqicn.org/city/
-https://www.airvisual.com/
(ご参考)バンコク中心部の観測地点における2019年1月1日~2月15日のPM2.5濃度(μg/m3)の推移
参照
https://www.beartai.com/article/tech-article/303260 https://thaipublica.org/2019/01/air-pollution-pm10-pm2-5/ https://www.bangkokpost.com/news/general/1610854/bangkok-air-pollution-remains-at-hazardous-levels http://www.nationmultimedia.com/detail/national/30343974?fbclid=IwAR3kN-1X0MXD2guaftMiNAWu9RuM83uH6d0p2LeI4NF1oApFBpv1ff2-FCg https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5876983/ https://aqicn.org/city/thailand/bangkok/chulalongkorn-hospital/ http://www.ccacoalition.org/en/content/air-pollution-measures-asia-and-pacific
From the investigations of the Forensics Department of the National Police Force, staffs of the Engineering Institute and staffs related to the incident, Mr. Pichaya Chantranuwat, the Director of the Engineering Institute of Thailand states that the origin of the fire is from the fire pump room on the B2 basement floor. The fire travelled from the underground floor B2 up to the 8th floor via the interconnecting duct between the B2 and 8th floor. The duct is horizontally installed and is made from fiberglass, which is not designed for high heat resistance. The heat spreading to the 8th floor’s duct caused it to collapse and obstruct the fire exit of the 8th floor which caused the smoke to be trapped and was not able to escape outside. The situation was worsened by large amount of combustibles which helped sustained and grow the fire.
Due to the old age of the building, the outdated duct design is considered to be a weak point. On the other hand, newly constructed buildings would have the heat resistant ducts installed or fire dampers inside the duct in order to prevent the air from coming inside. Building inspections for old buildings will be restricted to original structural inspections, and no emphasis will be made on the matters previously mentioned. Mr. Pichaya also states that the laws and regulations for building fires exist, but are difficult to enforce.
From our experience of surveying numerous factories, we hypothesize that the underground B2 floor, which contains the wastewater treatment equipment and other utilities, had methane gas, hydrogen sulfide gas, and ammonia gas accumulated from the wastewater treatment process. These gases can be ignited and catch fire quickly from electric sparks of the blower machine, which was inside the room, according to the news. This could be the cause of the fire incident. Afterwards, the smoke and heat rose into the ventilation duct which if no inspections were regularly performed, debris and residues could be the fire’s medium and helped spread the fire. This lead to continuous fire inside the duct due to the duct’s inability to resist fire, finally causing the pipe to be damaged, collapsing to block the exits.
[caption id="attachment_2260" align="aligncenter" width="225"] Traffic Congestions in Bangkok[/caption]
Area | Expected rainfall amount in rainy season 2018 (mm) | |||||
May | June | July | August | September | October | |
北部 | 178 | 156 | 176 | 223 | 218 | 124 |
北東部 | 187 | 203 | 211 | 266 | 242 | 117 |
中央部 | 172 | 145 | 156 | 181 | 257 | 187 |
東部 | 224 | 262 | 278 | 303 | 257 | 187 |
南部(東海岸) | 224 | 262 | 278 | 303 | 330 | 255 |
南部(西海岸) | 310 | 312 | 337 | 399 | 424 | 367 |
バンコク | 248 | 157 | 175 | 219 | 334 | 292 |
Have you ever wondered how our confidential or personal information leaks from us? Or how they fall into the wrong hands? The answers differs from a simple methods to advanced ones, so firstly for someone who may not be involved in cyber security to understand overall pictures is to know what is data breach? And where do data flow? Data breach is an incident where information is stolen or taken from a system without the knowledge or authorization of the system’s owner which can cause a small company or a large organization to suffer great loss. Stolen data may involve sensitive, proprietary, or confidential information, such as credit card numbers, customer data or trade secrets. There are so many ways data can easily leak out of an organization. There are three buckets or containers where information “lives and flows”; in digital form, in hard copy (paper) and in the conversation. Information is constantly flowing between these containers, usually resting in more than one of them at any given moment without some type of map or landscape that lays them all out. Data leak is divided into 2 classes which are internal data leakage and leakage from external threats. In total, there are shown 19 ways below.
貯水量:Sirikitダム
The malicious code refers to a broad category of programs that can cause damage or undesirable effects to computers or networks. Possible damage can include modifying, destroying or stealing sensitive data, gaining or allowing unauthorized access to a system and executing functions that a user never intended. So computer viruses are the most common form of malicious code. A virus is a program that infects a computer by attaching itself to another program and propagating itself when that program is executed. It should be noted that some malicious programs are able to exhibit the behaviors of more than one type of malicious code. For example, certain programs may be both a virus and a Trojan horse at the same time. Thus there are plenty of antiviruses are available in the market which uses different approaches to detect and remove viruses. Generally, these approaches can be distinguished into three categories 1) Signature-based detection 2) Heuristic-based detection and 3) Behavioral-based detection