二暴露區模式 (Two-Zone Model) 暴露評估工具

<% # 設置頁面編碼為 UTF-8 request$content_type("text/html; charset=utf-8") # 檢查是否為表單提交 is_post <- request$method() == "POST" # 初始化變數 G <- VN <- VF <- Q <- beta_val <- t_val <- MW <- 0 CN0 <- CF0 <- 0 twa_limit <- stel_limit <- idlh_limit <- oel_limit <- NA twa_unit <- stel_unit <- idlh_unit <- oel_unit <- "mg_m3" calc_option <- "time_dependent" results <- NULL if (is_post) { # 從表單獲取輸入值 params <- request$params() # 將輸入值轉換為數值 G <- as.numeric(params$G) VN <- as.numeric(params$VN) VF <- as.numeric(params$VF) Q <- as.numeric(params$Q) beta_val <- as.numeric(params$beta_val) t_val <- as.numeric(params$t_val) MW <- as.numeric(params$MW) CN0 <- as.numeric(params$CN0) CF0 <- as.numeric(params$CF0) twa_limit_val <- as.numeric(params$twa_limit) stel_limit_val <- as.numeric(params$stel_limit) idlh_limit_val <- as.numeric(params$idlh_limit) oel_limit_val <- as.numeric(params$oel_limit) twa_unit <- params$twa_unit stel_unit <- params$stel_unit idlh_unit <- params$idlh_unit oel_unit <- params$oel_unit calc_option <- params$calc_option # --- 單位轉換函數 --- # ppm 轉換為 mg/m3 ppm_to_mgm3 <- function(ppm, mw) { if (is.na(ppm) || is.na(mw) || mw == 0) return(NA) return(ppm * mw / 24.45) } # 根據選擇的單位進行轉換 twa_limit <- ifelse(twa_unit == "ppm", ppm_to_mgm3(twa_limit_val, MW), twa_limit_val) stel_limit <- ifelse(stel_unit == "ppm", ppm_to_mgm3(stel_limit_val, MW), stel_limit_val) idlh_limit <- ifelse(idlh_unit == "ppm", ppm_to_mgm3(idlh_limit_val, MW), idlh_limit_val) oel_limit <- ifelse(oel_unit == "ppm", ppm_to_mgm3(oel_limit_val, MW), oel_limit_val) # --- 核心計算函數 --- # 計算 lambda 1 和 lambda 2 calc_lambdas <- function(Q, beta_val, VN, VF) { # 確保分母不為零 if (VN == 0 || VF == 0) return(list(lambda1 = NA, lambda2 = NA)) term1 <- (beta_val * VF + VN * (beta_val + Q)) / (VN * VF) term2_sqrt <- (term1^2) - 4 * (beta_val * Q / (VN * VF)) # 檢查開根號項是否為負 if (term2_sqrt < 0) return(list(lambda1 = NA, lambda2 = NA)) lambda1 <- 0.5 * (-term1 + sqrt(term2_sqrt)) lambda2 <- 0.5 * (-term1 - sqrt(term2_sqrt)) return(list(lambda1 = lambda1, lambda2 = lambda2)) } # --- 計算邏輯 --- lambdas <- calc_lambdas(Q, beta_val, VN, VF) lambda1 <- lambdas$lambda1 lambda2 <- lambdas$lambda2 # 初始化結果列表 results <- list() # 檢查 lambda 是否有效 if (!is.na(lambda1) && !is.na(lambda2)) { time_points <- 1:t_val CN_t <- numeric(t_val) CF_t <- numeric(t_val) if (calc_option == "time_dependent") { # 功能1: 時間濃度解 if (lambda1 != lambda2 && beta_val != 0 && Q != 0 && VN != 0) { A <- G / Q * (beta_val / (beta_val + Q)) B_num <- beta_val * Q + lambda2 * VN * (beta_val + Q) B_den <- beta_val * Q * VN * (lambda1 - lambda2) B <- G * (B_num / B_den) C_num <- beta_val * Q + lambda1 * VN * (beta_val + Q) C_den <- beta_val * Q * VN * (lambda1 - lambda2) C <- G * (C_num / C_den) for(i in time_points) { CN_t[i] <- A + B * exp(lambda1 * i) - C * exp(lambda2 * i) } D <- G / Q for(i in time_points) { term_B <- G * ((lambda1 * VN + beta_val) / beta_val) * (B_num / B_den) * exp(lambda1 * i) term_C <- G * ((lambda2 * VN + beta_val) / beta_val) * (C_num / C_den) * exp(lambda2 * i) CF_t[i] <- D + term_B - term_C } } else { CN_t[] <- NA CF_t[] <- NA } results$CN_final <- CN_t[t_val] results$CF_final <- CF_t[t_val] } else if (calc_option == "steady_state") { # 功能2: 穩態濃度 if (Q > 0 && beta_val > 0) { CN_ss <- G / Q + G / beta_val CF_ss <- G / Q CN_t[] <- CN_ss CF_t[] <- CF_ss } else { CN_ss <- CF_ss <- NA } results$CN_final <- CN_ss results$CF_final <- CF_ss } else if (calc_option == "decay") { # 功能3: 濃度衰減 if (lambda1 != lambda2 && VN != 0) { for(i in time_points) { term1_num <- beta_val * (CF0 - CN0) - lambda2 * VN * CN0 term1_den <- VN * (lambda1 - lambda2) term1 <- (term1_num / term1_den) * exp(lambda1 * i) term2_num <- beta_val * (CN0 - CF0) + lambda1 * VN * CN0 term2_den <- VN * (lambda1 - lambda2) term2 <- (term2_num / term2_den) * exp(lambda2 * i) CN_t[i] <- term1 + term2 cf_term1_factor <- (lambda1 * VN + beta_val) / beta_val cf_term2_factor <- (lambda2 * VN + beta_val) / beta_val CF_t[i] <- cf_term1_factor * term1 + cf_term2_factor * term2 } } else { CN_t[] <- NA CF_t[] <- NA } results$CN_final <- CN_t[t_val] results$CF_final <- CF_t[t_val] } results$time_points <- time_points results$CN_t <- CN_t results$CF_t <- CF_t # --- TWA 和 STEL 計算 --- if(t_val > 0 && !any(is.na(CN_t))) { # TWA 計算 (基於近場濃度) results$twa_calc <- sum(CN_t) / 480 # STEL 計算 (基於近場濃度，取最大15分鐘移動平均) if (t_val >= 15) { rolling_sums <- zoo::rollapply(CN_t, width = 15, FUN = sum, align = "right") results$stel_calc <- max(rolling_sums / 15) } else { results$stel_calc <- sum(CN_t) / 15 # 如果時間不足15分鐘，則以現有時間計算 } } else { results$twa_calc <- NA results$stel_calc <- NA } # --- 風險分級 --- risk_table <- data.frame( Parameter = character(), Exposure_Limit = character(), Calculated_Value = character(), Risk_Ratio = character(), Risk_Level = character(), stringsAsFactors = FALSE ) # 1. IDLH if (!is.na(idlh_limit)) { peak_conc <- if(length(CN_t) > 0) max(CN_t, na.rm = TRUE) else NA risk_ratio <- if (!is.na(peak_conc)) peak_conc / idlh_limit else NA level <- if (!is.na(risk_ratio) && risk_ratio > 1) "4 (立即危害)" else "低於立即危害濃度" risk_table[nrow(risk_table) + 1,] <- c("IDLH (短期)", paste(round(idlh_limit, 2), "mg/m³"), paste(round(peak_conc, 2), "mg/m³ (峰值)"), if(!is.na(risk_ratio)) round(risk_ratio, 2) else "N/A", level) } # 2. STEL if (!is.na(stel_limit)) { risk_ratio <- if (!is.na(results$stel_calc)) results$stel_calc / stel_limit else NA level <- if (!is.na(risk_ratio) && risk_ratio > 1) "4 (有健康危險)" else "可接受" risk_table[nrow(risk_table) + 1,] <- c("STEL (短期)", paste(round(stel_limit, 2), "mg/m³"), paste(round(results$stel_calc, 2), "mg/m³ (15分鐘)"), if(!is.na(risk_ratio)) round(risk_ratio, 2) else "N/A", level) } # 3. TWA if (!is.na(twa_limit)) { risk_ratio <- if (!is.na(results$twa_calc)) results$twa_calc / twa_limit else NA level <- if (is.na(risk_ratio)) "N/A" else if (risk_ratio > 1) "4" else if (risk_ratio > 0.5) "3" else if (risk_ratio > 0.1) "2" else "1" risk_table[nrow(risk_table) + 1,] <- c("TWA (長期)", paste(round(twa_limit, 2), "mg/m³"), paste(round(results$twa_calc, 2), "mg/m³ (8小時)"), if(!is.na(risk_ratio)) round(risk_ratio, 2) else "N/A", level) } # 4. OEL (與 TWA 比較) if (!is.na(oel_limit)) { risk_ratio <- if (!is.na(results$twa_calc)) results$twa_calc / oel_limit else NA level <- if (is.na(risk_ratio)) "N/A" else if (risk_ratio > 1) "4" else if (risk_ratio > 0.5) "3" else if (risk_ratio > 0.1) "2" else "1" risk_table[nrow(risk_table) + 1,] <- c("OEL (長期)", paste(round(oel_limit, 2), "mg/m³"), paste(round(results$twa_calc, 2), "mg/m³ (8小時)"), if(!is.na(risk_ratio)) round(risk_ratio, 2) else "N/A", level) } results$risk_table <- risk_table # --- 建議控制措施 --- final_risk_level <- 0 if (any(risk_table$Risk_Level %in% c("4 (立即危害)", "4 (有健康危險)"))) { final_risk_level <- 4 } else { levels <- as.numeric(risk_table$Risk_Level) if(any(!is.na(levels))) final_risk_level <- max(levels, na.rm=TRUE) } results$control_measures <- switch(as.character(final_risk_level), "1" = "管理等級 1 (低風險): 建議維持良好作業環境，持續進行通風與環境整理。", "2" = "管理等級 2 (中度風險): 建議改善整體換氣裝置，或考慮局部抽氣裝置。", "3" = "管理等級 3 (高風險): 應立即採取有效的工程控制，如安裝密閉系統或局部抽氣裝置，並考慮使用個人防護具。", "4" = "管理等級 4 (極高風險): 立即停止作業！尋求工業衛生專家協助，重新評估作業流程與控制措施，在改善前不可復工。", "0" = "無法評估風險等級，請確認輸入值。", "無法評估風險等級，請確認輸入值。" ) } else { results$error <- "輸入參數錯誤，無法計算 λ (lambda) 值 (例如: 根號內為負數或體積為零)。" } } %>

輸入參數

污染源排放速率 (G) (mg/min)

近場體積 (V_N) (m³)

遠場體積 (V_F) (m³)

房間通風換氣速率 (Q) (m³/min)

近場與遠場間空氣交換速率 (β) (m³/min)

作業/模擬時間 (t) (min)

暴露限值

化學物質分子量 (MW) (g/mol)

TWA (8小時日時量平均容許濃度)

>mg/m³ >ppm

STEL (短時間時量平均容許濃度)

>mg/m³ >ppm

IDLH (立即危害生命健康濃度)

>mg/m³ >ppm

其他 OEL (暴露限值)

>mg/m³ >ppm

計算功能選擇

> 功能1：時間濃度解 (逸散中)

近場 (公式7-1): \( C_{N}(t) = \frac{G}{(\frac{\beta}{\beta+Q})Q} + G[\frac{\beta Q+\lambda_{2}V_{N}(\beta+Q)}{\beta QV_{N}(\lambda_{1}-\lambda_{2})}]e^{\lambda_{1}t} - G[\frac{\beta Q+\lambda_{1}V_{N}(\beta+Q)}{\beta QV_{N}(\lambda_{1}-\lambda_{2})}]e^{\lambda_{2}t} \)
遠場 (公式7-2): \( C_{F}(t) = \frac{G}{Q} + G[\frac{\lambda_{1}V_{N}+\beta}{\beta}][\dots]e^{\lambda_{1}t} - G[\frac{\lambda_{2}V_{N}+\beta}{\beta}][\dots]e^{\lambda_{2}t} \)

> 功能2：穩態濃度

近場 (公式7-3): \( C_{N,SS} = \frac{G}{Q} + \frac{G}{\beta} \)
遠場 (公式7-4): \( C_{F,SS} = \frac{G}{Q} \)

> 功能3：濃度衰減 (污染源停止逸散)

請在下方輸入初始濃度：

近場初始濃度 (C_N0) (mg/m³)

遠場初始濃度 (C_F0) (mg/m³)

近場 (公式7-5): \( C_{N}(t) = \frac{\beta(C_{F_{0}}-C_{N_{0}})-\lambda_{2}V_{N}C_{N_{0}}}{V_{N}(\lambda_{1}-\lambda_{2})}e^{\lambda_{1}t} + \frac{\beta(C_{N_{0}}-C_{F_{0}})+\lambda_{1}V_{N}C_{N_{0}}}{V_{N}(\lambda_{1}-\lambda_{2})}e^{\lambda_{2}t} \)
遠場 (公式7-6): \( C_{F}(t) = \frac{(\lambda_{1}V_{N}+\beta)}{\beta}[\dots]e^{\lambda_{1}t} + \frac{(\lambda_{2}V_{N}+\beta)}{\beta}[\dots]e^{\lambda_{2}t} \)

開始計算

<% if (is_post && !is.null(results)) { %> <% } %> 列印結果